Apparatus for the electrical treatment of gases



'c. w. J. HEDBERG. APPARATUS FOR THE ELECTRICAL TREATMENT OF GASES.

APPLICQTION FILED FEB. 261 i918.

Patented Oct. 28, 1919.

izkluw emima,

TED STATES PATENT OFFICE.

CARL WM. J". HEDBERG, OF NEW BRITAIN, CONNECTICUT, ASSIGNOR TO RESEARCHCORPORATION, OF NEW YORK, N. Y.,

A CORPORATION or New YORK.

LIMSRYOU.

Specification of Letters Patent.

Patented Oct. 28, 1919.

Application filed February 26, 1918. Serial No. 219,305.

To all whom it may concern.

Be it known that I, CARL WILLIAM JULIUs Hnnnnne, a. citizen of theUnited States, residing at New Britain, in the county of Hartford andState of Connecticut, have invented certain new and useful Improvementsin Apparatus for the Electrical Trcz ment of Gases, of which thefollowing is a specification.

The present invention relates to apparatus for removing suspendedparticles from gases or gaseous mixtures by the application of highpotential electric charges.

In apparatus of this character comprising principally discharge andcollecting electrodes a field of intense electric stress is produced,through which the gases are passed. The suspended particles are chargedby the discharge electrode and i'nigrate under the influence of thischarge toward the collecting electrode.

It is customary to make the discharge electrode of a wire or otherlongitudinally extending conducting element and the collecting electrodein the form of a plate, box or cylindrical tube. The discharge electrodepresents a small surface with the result that the electric field ishighly concentrated and forms a zone of stress of great intensity, whilenear the collecting electrode,'on the other hand, since it presents arelatively large area, the intensity of the field is small. The theoryon which the arrangement is based is that the particles suspended in thegases should be intensely charged near the discharge electrode to forcethem transversely of the gas stream toward the collecting electrode andthat the collecting electrode in turn should not be able to neutralizethis charge or even reverse it. It is the idea to make the migrationsubstantially unidirectional and thereby prevent particles once forcedout of the active zone from being returned to it.

Some particles drop, due to their own gravity, down through the inactivezone near the collecting electrode into a collecting chamber. Othersagglomerate and in that condition fall through the inactive zone intothe collecting chamber. Still others ,are carried along due to thevelocity of the gas. The greater portion, however, of the particles areforced against the collecting electrode and collect thereon or adherethereto forming a gradually increasing deposit.

Such deposit is detrimental to the operation of the apparatus and mustbe periodically removed.

It is the general object of the present invention to remove suspendedparticles from gases and a more particular ohjectfto keep the collectingelectrodes clean while the particles are removed.

Another object is the removal of dust, fumes and other suspendedparticles from swiftly moving gases.

The apparatus embodying the invention, in order to carry out the objectsmentioned, deviates in principle from the usual types above referred toin that the collecting electrode does not present a large surface, coextensive withthe discharge electrode, but has the form of transversewebs presenting circular edges toward the discharge electrode andconcentric therewith.

The purpose and specific advantages of this construction will appearmore clearly in connection with the accompanying drawings, in whichFigure l is an elevation partly in section, and

Fig. 2 a transverse section on line 22 of Fig. 1.

In the drawings, 1 represents a box-like structure forming the treaterchamber. The gases enter this chamber through the conduit 2, flowupwardly in the chamber and pass ofl' into the atmosphere or may beconducted to some particular place for use or further treatment. In thechamber 1 there are a plurality of transverse webs 3 arranged in tiersfrom bottom to top. These transverse webs 3 have a relatively largenumber of perforations t, equal in size and equally spaced, and theperforations of the different tie-rs are all in vertical alinement. T hewebs are of electrical conducting material and constitute in theirentirety a collecting electrode.

Through the vertically alined openings 4 extend longitudinally extendingconductors such as fine wires 5 which form the discharge electrodes.These wires are supported by a frame 6 resting on insulators 7 on the.top

spacing frame 10 and weights 11 may be attached thereto to hold thewires taut. The

between the central or discharge electrode and the webs or collectingelectrodes, charges are induced .upon the suspended particles or theyreceive charges from= the ionized gases. These charges move under theinfluence of the electric fields and take with them the suspendedparticles to which they are attached. The fields are strongest and themovement of particles is greatest between the discharge electrode andthe orifice edges, but the particles do not come to rest in the intenseparts of the fields, seeking rather the weak fields adjacent thoseportions of the webs which are at a distance from the orifices.

This characteristic may be explained in partby calling attention to thephenomenon commonly called electric wind. The molecules of the gaseswhich have become ionized, and are called ions, and the suspendedparticles to which electric charges are attached, are propelled rapidlythrough the gases by the force of the electric field. The movement ofthese particles and molecules has an aspirating. effect upon adjacentgas molecules setting them in motion, the direction being from thestrongest to the weakest part of the field. It is conceded that thereare charges of both positive and negative sign present in the gases andthey tend to move in opposite directions, but

- those which tend to move counter-current to the electric wind have toovercome considerable resistance and are probably swept back orneutralized, especially if these charges are endeavoring to take withthem suspended articles. By making the central electro e of negativepolarity the move-v ment of gases is set up by electrons and negativeions which have a higher velocity 1 than positive ions and the resultsdescribed above are thenthe most pronounced and most satisfactory. Infact it is found that practically no particles get to thecentralelectrode and settle upon it. In some instances it has been advantageousto have the orifice edges comparatively shar and the corresponding fieldstrength ad acent. thereto correspondin ly great which tends to give aslight back-ionization and a resistance to the depositing of particles,but it is probably the momentum of the particles,

potential drop per unit of dielectric distance is considerably increasedand thereby the electric stress or ionizing capacity.

The direct result is a general increase of the efiiciency of thetreater. .This form of device is particularly adapted for the treatmentof swiftly moving gases.

A distinct advantage gained is that by this arrangement the particlesonce precipitated are definitely removed from the gas stream. The zonesintermediate the orifices 4 are outside the gas current and there is noforce tending to bring them back into it.

It is further apparent from this arrangement that the current of dustladen gas as it passes through the apparatus is subjected to repeatedchanges in direction and velocity of gas flow. The velocity of the gascurrent is increased as it passes through the orifices and then isdiminished as it expands into.

particles from the tre-ater, the transverse webs 3 are divided into aplurality of pivotally' mounted sections 16. The line of divisionbetween the separate sections lies substantially in the planes passingthrough the rows of discharge electrodes and the pivotal moyement takesplace in planes centrally between the discharge electrodes. to which thesections 16 may be connected in any suitable manner, extend through thechamber 1 .and have bearing in opposite walls thereof. At one side theserods 17 extend beyond the outer surface of the wall so that suitablemeans may. be provided forturning them. In the particular instancecranklevers 18 are secured to the rods. At their outer ends these cranklevers 18 are provided with slots 19. The crank levers 1.8 of each tierare inter onnected. by rods Rods 17,

essary to start the motor 30 joints comprising levers 25 and, bell orbars 20 having laterally projecting pins 21. These pins 21 extend intotheslots 19 and are so spaced along rods 20 that all crank levers 18have the same angular position. When the rods 20 are reciprocated, thecranks are simultaneously turned through an angle indicated by therelative -positions of the cranks in the two bottom rows in Fig. 1. Bythus turning the cranks the sections 16 are turned from the positionshown in the bottom row to that shown in the second row in Fig. 1, sothat the deposit may drop down into a collecting chamber or hopper (notshown) where it may be removed.

To facilitate the separation of the deposit from the sections 16,provisions aremade for jarring or knocking them during their turningmovement. As a convenient means I have shown bars or rods 22 mountedparallel to the pivotal rods 17 and positioned in the path of rotarymovement of the sections 16, as indicated in Fig. 1, second row. Therods 20 may be mounted in bearings 23 \attached on the outside of thechamber 1. To operate all rods 20 simultaneously, they areinterconnected by an arm 24 and toggle cranks 26 pivotallyinterconnected in a manner well understood; The arm 24 terminates in aslotted cross arm 27 engaged by the crank pin 28 on a crank driven by amotor 30 all as .is well understood. The arm 24 is supported for slidingmovement in bearings 31 attached to the wall of the'cha mber 1.

As indicated, the sections 16 preferably contact along oblique planesfor the purpose of alinement and mutual support.

The operation is apparent from the preceding description. When it isdesired to rap the collecting electrodes, it is only necwithout firstdisconnecting the apparatus from the line.

In the foregoing an attempt has been made to merely 'outline the broadprinciples governing the invention. It is, of course, not necessary tomove the orifice plates into alinement each time they are jarred. Thetranslating mechanism may be suitably modified so that the orificeplates repeatedly strike the member 22 without each time returning tothe alining position.

In practice the orifice plates may be placed closer together than shownin the drawing as is obvious. In fact, while I have shown all orificeplates as simultaneously operated for tilting movement, I contemplatethe separate tilting of the different tiers commencing with the top tierand successively going down to the bottom tier.

I may also restrict the pivotal movement of the orifice plates to arelatively small angle, where the deposit is such that it may be easilyremoved from the plates.

While I have suggested a tilting of the disk 29 which may be plates forremoving the deposit thereon, such tilting movement is not absolutelyessential and provisions may be made for removing the deposit in otherways and by difi'erent means than by rotation.

I contemplate these and such other changes as may readily suggestthemselves during the application of my invention to differentconditions.

l Vhat is shown and described is merely for the purpose of illustration.

I claim t .1. In apparatus for the electric treatment of gases, atreater chamber, a collecting electrode consisting of a plurality ofspaced electric-ally interconnected plates in said chamber, a pluralityof orifices in each plate, each orifice in each plate beingsubstantially in alinement with an orifice in each of the other platesand a discharge electrode extending through each space defined by alinedorifices.

In apparatus for the electric treatment of gases, at treater chamber, aplurality of spaced plates in parallel arrangement constitutingcollecting electrodes, alined orifices in said plates to form a conduitfor the gases, a discharge electrode extending through said conduit andmeans for rapping the plates.

3. In apparatusfor the electric treatment of gases, a collectingelectrode comprising a treater chamber and a plurality of verticallySpaced electrically interconnected plates therein in parallelarrangement, alined orifices in said plates to form a conduit for thegases, a discharge electrode extending through the said conduit andmeans for removing deposit from the said plates.

4. In apparatus for the electric treatment of gases, at collectingelectrode comprising a treater chamber and a plurality of verticallyspaced plates therein in parallel arrangement, alined orifices in saidplates to form a conduit for the gases, a discharge electrode extendingthrough the said conduit and means acting on the said plates to removedeposit therefrom while the elec trodes are charged.

5. In apparatus for the electric treatment of gases, a collectingelectrode comprising a treater chamber and a plurality of verticallyspaced plates therein in parallel arrangement, alined orifices in saidplates to form a tonduit for the gases, a discharge electrode extendinginto for tilting at will the said plates.

6. In apparatus for the electric treatment of gases, a collectingelectrode comprising a treater chamber and a plurality of vertithe saidconduit and means;

rangement, alined orifices in said plates to' form a conduit for thegases, a discharge electrode extending, into the said conduit, means fortilting at will the said plates and means for rapping said plates duringthe tilting movement.

7. In apparatus for the electric treatment of gases, a collectingelectrode comprising a treater chamber and a plurality of verticallyspaced plates pivotally mounted therein, alined orifices in said platesto form a conduit for the gases, a discharge electrode extending intothe said conduit, means for turning the plates about their pivots andmeans for rapping them during such turning movement. I

8. In apparatus for the electric treatment of gases, at collectingelectrode comprising a treater chamber and a plurality of'electricallyinterconnected vertically spaced plates therein, a plurality of orificesin each plate, each orifice in each plate being substantially inalinement With an orifice in each of the other plates, a dischargeelect-rode extending into each space defined by alined orifices andmeans forremoving deposit from the said plates.

9. In apparatus for the electric treatment of gases, a collectingelectrode comprising a treater chamber and plurality of verticallvspaced plates therein, a plurality of orifices in each plate, eachorifice in each plate being substantially in alinement with an orificein each of the other plates, a dischar e electrode extending into eachspace defined by alined orifices and means acting onthe said plates toremove deposit theretransversely thereof,

from while the electrodes are charged.

10. In apparatus for the electric treatment of gases, a collectingelectrode comprising a treater chamber and a partition said partitionbeing composed'of a plurality of pivotally mounted sections constructedand arranged to define a plurality of orifices, a discharge electrodeextending into each orifice and means for turning each section about itspivot.

11. In apparatus for the electric treatment of gases, a collectingelectrode comprising a treater chamber and a partition transverselythereof, said partition being composed of a plurality of pivotallymounted sections constructed and arranged to define a plurality oforifices, a discharge electrode extending into each orifice, means forturning each section about its pivot and means for rapping it duringsuch turning movement.

12. In apparatus for the electric treatment of gases, a collectingelectrode comprising a treater chamber and a partition transverselythereof, said partition being composed of a plurality of pivotallymounted sections constructed and arranged to define a plurality oforifices, a discharge electrode extending into each orifice, means forsimultaneously turning said sections about their pivots.

13. In apparatus for the electric treatment of gases, a collectingelectrode comprising a treater chamber and a partition transverselythereof, said partition being composed of a v plurality of pivotallymounted sections constructed and arranged to define a plurality oforifices, a discharge electrode extending into each orifice,means forsimultaneously turning said sections about their pivots and means forrapping the sections during such turning movement.

In testimony whereof I afiix my signature in presence of two witnesses.

CARL WM. J. HEDBERG.

Witnesses:

ROBERT B. On, MARGARET E. OTT.

